The long-term objective is to understand the structure-function relationships of the various mammalian liver aldehyde dehydrogenases. The Specific Aim is to characterize the primary structures of the up to nine normal and inducible isozymes of rat liver aldehyde dehydrogenase (ALDH). We will use this information to: (a) Establish the interrelationships among the various normal liver and/or inducible rat liver ALDHs. (b) Correlate rat ALDH isoenzyme primary structures with those of the human and horse liver mitochondrial and sytosolic isozymes. (c) Refine current predictions concerning structure-function relations within and between various mammalian aldehyde dehydrogenases. By fulfilling the Specific Aim, we will have completed the first detailed primary structure analysis of all members of the rat liver aldehyde dehydrogenase enzyme family. Additionally, we will have significantly increased our knowledge of the structure/function interrelationships between the various mammalian liver aldehyde dehydrogenases.